Lack-of-liquid safety device for liquid heaters



Feb. 24, 1942.

F. WEBER 2,274,017

LACK-OF-LIQUID SAFETY DEVICE FOR LIQUID HEATERS Filed Nov. 18, 1939 3Sheets-Sheet 1 ig I I 23 Z9 Z5 3/ [77V6V77L0F/ 9 W M/JW Feb. 24, 1942.F. WEBER 2,274,017

LACK-OF-LIQUID SAFETY DEVICE FOR LIQUID HEATERS Fild Nov. 18, 1939 3Sheets-Sheet 2 Eye , 4/ I 1$ r b 2a 7a 24 [/1 yen/0n aim! h/JW liq/02mFeb. 24, 1942.

LACK-OF-LIQUID SAFETY DEVICE FOR LIQUID HEATERS Filed Nov. 18, 1939 3Sheets-Sheet 5 F. WEBER r 2,274,017

PatentedfFeb. 2 4, 1942 LACK-OF-LIQUID SAFETY DEVICE FOR LIQUID HEATERSFriedrich Weber, Dessau, Anhalt, Germany, as-

signor to Junkers & Co. G. m. b. IL, Dessau,

Germany Application November 18, 1939, Serial No. 305,148 In GermanyDecember 22, 1938 8 Claims.

This invention relates to a lack-of-liquid safety device for the fuelvalves of liquid heaters, with a change-over device developed in form ofa cock plug, by means of which it is possible to convey the fresh waterto the heater, as well as to the warm-water discharge line of theheater.

With the hitherto known devices of this kind, the changeover is locatedat one side of the lackof-liquid safety device, in approximately thesame plane with the warm-water outlet and the fresh-water intake valves,thus requiring careful subdivisioning of the lateral space available forthe valves and the change-over device, at the housing of thelack-of-liquid safety device. Moreover, with the known devices, theliquid, r,egulating valve provided in the housing, andga'ctuated bythewadjusting member of the lack-of:- liquid safety device, is notaccessible until after the dismantling of the whole housing.

According to the invention the change-over device is located in thecentre and in the axial direction of the adjusting" member of thelack-ofliquid safety device, serving at the same time as a support for aliquid regulating valve influenced by the adjusting member.

All this results in an essential simplification,

and cheapening in cost,'of the whole lack-of-liquid safety device,because the location, in the sense of the invention, of the change-overdevice at the bottom side of thehousing provides more space for thevalves, or the like, to be lo- ,cated at one side of the housing, thusmaking it possible, in connection with a corresponding sim- Figure 1shows a vertical section through the lack-of-liquid safety device inconnection with the gas section of a liquid heater and Figure 2 ahorizontal section through the lackof-liquid safety device, along theline 22 in Figure 1, whilst Figures 3 to 5 diagrammatically depictvarious positions of adjustment of the change-over device conforming tothe invention.

Between the lower part I and the upper part.

2 of the housing of the lack-of-liquid safety device, a diaphragm} isfastened in a generally known manner, such diaphragm subdividing theinterior of the housing into a high-pressure chamber 4, located belowthe diaphragm, and a low-pressure chamber 5, located above thediaphragm. The diaphragm 3 is in mechanically controlled connection witha control stud 6 controlling the gas valve located in the housing I.

As especially made visible in Figure 2, the lower part I of the housingis provided with a tubular connecting piece 8 for connecting thefreshwater supply line 9, and with a tubular connecting piece l0 forconnecting the piping ll (Figures 3 to 5) leading to the heater. Thetubular connecting piece I0 is provided with a Venturl tube l2 of which,in a generally familiar manner, the narrowest part is in connection withthe lowpressure chamber 5 by way of a bore IS in the Venturi tube, and abore H in the correspondv ingly developed tubular connecting piece ID inplification of the housing, to locate the bores for these valves, or.the like, in a simple and easily executable manner. An additionaladvantage is to be found in the fact that the liquid regulating valvemay be withdrawn by simply withdrawing the plug of the change-over cockfrom the housing, and that at the housing of the lack-ofliquid safetydevice no spots or surfaces requiring machining for attaching the liquidregulating valve need be provided. Furthermore, the arrangement anddevelopment of the change-over device in the sense of the inventionfacilitates simple and accessible arrangement of the service handle ofthe change-over device, so that the manipulation of the service handleis not obstructed by any valves, or the like, located at close distance.

Further characteristic features of the invention are set forth in thefollowing description.

To enable the invention to be fully understood it will now be describedwith reference to the accompanying drawings in which:

which a check valve [5, diagrammatically indicated in Figures 3 to 5, islocated. Furthermore, for the connection of a water line I6 (Figures 3to 5) coming from the heater, still another tubular connecting piece I!is provided which, in addition, may be equipped with a connecting pointl8 for connecting a warm-water discharge line. At the lower part i ofthe housing, the tubular connecting piece I! empties into a bore I9developed as a valve seat, which bore can be shut off by means of avalve body 2| to be actuated by a handle 20. To the valve space 22,which can be shut off. by the valve body 2|, the water outlet 23 of thedevice is connected.

In the centre and in the axial direction of the adjusting member 3, thechange-over device, developed in the form of a cock plug 24, is locatedin the lower part I of the housing. The cock plug 24 is provided with anunder-cut tenon 25 protruding from the lower part I of the housing, towhich tenon a cap 21 is fastened by means of a screw 26, this cap beingprovided with a service handle 28 for turning the cock plug 24. By meansof a washer 30, which by the screw 29 for the stuffing box packing isfirmly pressed against a shoulder in the bore of the cock plug, the cockplug is protected from withdrawal, whilst any movement of the cock plugtoward the interior is prevented by means of the cap 27 slidinglybutting up against the bottom side of the lower part I of the housing;The service handle 28 is provided with an attachment 3| which during themovement of the cock plug moves over an adjusting scale 32 provided onthe circular side wall of the housing indicated in a broken line inFigure 2. At the same time, attachment 3| serves as a handle and,together with the tubular connecting piece l1 and the housing of thevalve 2|, as a stop for limiting the movement of the cock plug. Theinner end of the cock plug 24 is provided with a bore 33 serving as awater passage and, at the same time, as a regulating chamber; which boreis shut off toward the high-pressure chamber 4 by a threaded body 35provided with a valve-seat bore 34; in such bore there being locatedalso a movable valve body 31 developed in the form of a float regulator,the lower end of such valve body being provided with a valve seatsurface 36. The upper end of the valve body 31 protrudes from thevalve-seat bore 34 into the high-pressure chamber 4, and is providedwith a head 38 smaller than the bore 34, so that the whole valve body 31may be made in one piece, and that, after it has been inserted into theregulating chamber 33, the threaded body 35 can be screwed into the cockplug. The lower end of the valve body 31 is provided with flats 39 forwater passage. By means of a cross bore 49 through the cock plug, theregulating chamber 33 can be connected to the freshwater supply line 8,9. Furthermore, the cock plug seat in the lower part i of the housing isprovided with a bore 4| (Figure 2) which, at a corresponding position ofthe cock plug 24, and, by way of bore 40 of the cock plug, can be madeto connect with the fresh-water supply line, and empties directly intothe highpressure chamber 4. In addition, and below the regulatingchamber 33, the cock plug 24 is provided with a continuous cross bore 42through which the fresh water can directly reach the outlet 23.

After the lifting of the bonnet 21 and of the threaded connection 29,the cock plug, together with the whole liquid regulating valve, can bewithdrawn from the housing The device described hereinabove worksasfollows, as especially made'clear also by the drawings 3 to 5: v

First of all, attention is drawn to the fact that, in Figures 3 to 5,contrary to Figures 1 and 2, and for the purpose of simplifying thediagrammatical description, the fresh-water intake 8, 9 is provided atthe left side of the cock plug 24.

Figure 3 shows the cock plug 24 in the position for hot water. In thiscase, the fresh water coming from the supply line 8, 9 reaches theregulating chamber 33 by way of the bore 40 in the cock plug 24. Whenthe water supply to the heater is opened the valve body 31 is lifted bythe flow of the water so that the head 38 of the valve body is pressedagainst the lower surface of the diaphragm 3. In case the water flows atlow speed to the heater, the diaphragm 3 is lifted only a little owingto the small suction effect of the Venturi tube I2. Consequently alsothe valve body 31 is lifted only a little so that the thin middleportion of the valve body 31 releases or provides the largest possiblepassageway through the valve-seat bore 34. When, however, the speed ofthe flowing water rises, the diaphragm 3 and accordingly the valve body31 are lifted to a higher position so that the valve seat surface 36 ofthe valve body is brought close to the valve seat bore 34, and thepassageway of said bore is more or less obstructed. In this manner thewater flowing through the valve bore 34 to the high-pressure chamber 4and then to the heater is automatically regulated. From thehigh-pressure chamber 4 the Water flows through the Venturi tube i2 andthrough the piping II to the heater in Figure 3 diagrammatically shownas a broken and dotted line. In that connection, the diaphragm isadjusted in the generally known manner, and by means of the control studB the gas valve actuated. The hot water, having passed the heater,reaches the outlet 23 by way of the Water line Hi and the valve 2|. Ifthe water outlet valve 2| is now closed, this will stop the flow ofwater through the heater and through high pressure chamber 4 and Venturitube I2 so that the pressures in chambers 4 and 5 are equalized, causingthe gas valve to be closed by spring pressure. Also, when the watersupply to the heater is shut off for any reason, that is to say, when alack-of-liquid occurs, the same action takes place because due to alack-of-liquid flow, the pressures on both sides of diaphragm 3 areequalized. The diaphragm therefore returns to its normal position andthe gas valve is immediately closed to prevent any overheating or otherdamage to the water heater. Thus it will be seen that the lack-of-liquidsafety device just described operates to prevent damage as soon as alack-of-liquid" occurs and that this device operates when flow of liquidthrough the heater is prevented either at the inlet or the outletthereof. a

Figure 4 shows the cock plug 24 adjusted for warm water. In thatposition, the bore 40 of the cock plug connects the fresh-water supplyline 8, 9 with .the bore 4| in the lower part I of the housing. Thus,the fresh water reaches the high-pressure chamber 4 not only by way ofthe liquid regulating valve, as shown in Figure 3, but part of the freshwater, by-passing the regulating valve, also and directly enters thehighpressure chamber 4 by way of the bore 4|. Thereby, the quantity ofwater flowing to the \heater is increased and the temperature of thedischarged water decreased.

Figure 5 shows the cock plug 24 adjusted to such a position that thefresh-water supply line 8, 9 is directly connected with the outlet 23 byway of the bore 42 of the cock plug, so that the fresh-water supply forthe heater is completely shut off.

Figure 2 of the drawings shows that a further turning to the left of thecock plug 24 away from its position according to Figure 5 results incompletely shutting ofi the water supply. Consequently, with thearrangement conforming to the invention the hitherto required separateshut off valve for the fresh-water supply is entirely dispensed with,resulting in an additional simplification, and cheapening of cost, ofthe whole device.

Naturally, the herein described liquid regulating valve may be developedin some other form also. For instance, in the place of the floatregulator 31 the movable valve body may, in ,the generally known manner,by means of a spring be kept in mechanically controlled contact with theadjusting membe actuated by the water pressure. In such a case, with adevice conforming to the invention, the spring would have to be arrangedin such a manner that its lower end would rest upon that part of thecock plug 24 which protrudes into the high-pressure chamber 4, so thatthe spring, together with the liquid regulating valve and the cock plug24, may be withdrawn from the housing I.

Having now particularly described and ascertain'ed the nature of oursaid invention and in what manner the same is to be performed, I declarcthat what I claim is:

1. A lack-of-liquid safety device for water heaters comprising a fuelvalve for said heater, an adjusting member for actuating said fuelvalve. a housing surrounding said adjusting member and including highand low water-pressure chambers on opposite sides of said adjustingmember, a water regulating valveoperable to automatically control theflow of water through said device and arranged centrally of and operableby said adjusting member', a change-over device including passagesformed in said housing for flow of water to and from the heater and acock-plug having water-passage bores for controlling'said passages andoperable to convey fresh water to the heater or to the warm waterdischarge line of said heater, said cock-plug being arranged centrallyof and below said adimting member and in coaxial alinement with saidfuel valve and fitted into a bore formed in said housing and connectingthe fresh water supplypassage with the high pressure chamber below saidadjusting member. the inner end of said cock-plug supporting said waterregulating valve.

2. A lack-of-liquid safety device as set out in claim 1 in which thebore in which the cockplug and the water regulating valve supportedthereby are mounted is formed as an opening provided in an outside wallof said housing and the cock-plug and water regulating valve can bemounted therein and withdrawn therefrom as a unit, and means forremovably mounting and holding said cock-plug in said opening.

3. A lack-of-liquid safety device as set out in claim 1 in which saidcock-plug contains horizontal and vertically extending bores whichcooperate with the wateginletgand discl'nrge passages of said housingwhereby said. cock-plug is operable to direct fresh water either to thewater heater inlet or to the discharge and to regulate the amount ofwater delivered to said water heater.

4. A lack-of-liquid safety device according to claim 1. in which thewater passage of the cockplu'g, through which the fresh water isdirectly conveyed to the warm-water outlet, comprises cross bores, whilethe water passage of said cockplug leading'to the high-pressure chambercomprises a longitudinal bore with a cross-wise running connecting bore.

5. A lack-of-liquid safety device as set out in claim 1 in which saidcock-plug contain horizontal and vertically extending bores whichcooperate with the water inlet and discharge passages of said housingwhereby said cock-plug is operable to direct fresh water either to thewater heater inlet or to the discharge and to regulate the amount ofwater delivered to said water heater, said liquid regulating valvecontrolling said vertical bore and being operated by the pressure of thewater in said bore.

6. A lack-of-liquid safety device for liquid heaters as set out in claim1 in which said liquid regulating valve is arranged in one of thepassages in said cock-plug, the passages in said cock-plug and housingbeing arranged so that in one position of said cock-plug water flowsfrom the fresh water supply passage to said heater inlet through saidcock-plug and said regulating valve only and in another position of saidcockplug flows through said cock-plug and both through said regulatingvalve and through a bypass thereof. 7

7. A: lack-of-liquid safety device according to claim 1, in which thewater regulating valve comprises a movable valve body which acts as afloat regulator and is actuated by the water pressure, said movablevalve body being in a valveseat bore provided in a releasable sealingpart mounted in the hollow end of said cock-plug and cooperatingtherewith to provide a float chamber, the upper head of such movablevalve body being of smaller diameter than the valve-seat bore of saidreleasable sealing part.

A lack-of-liquid safety device according to claim 1, in which thecock-plug is provided with a service handle having an attachmentextending finin the bottom side of the housing around the latter'scircular side wall, such attachment being movable over an adjustingscale provided on thecircularwall of the housing, and-serving as ahandle portion and, together withcorrespondingpartsofthehousing,asastopforlimitingthe movement on bothsides.

FRIEDRICH WEBER.

